Gyratory crushers are used for crushing ore, mineral and rock material to smaller sizes. Typically, the crusher comprises a crushing head mounted upon an elongate main shaft. A first crushing shell (typically referred to as a mantle) is mounted on the crushing head and a second crushing shell (typically referred to as a concave) is mounted on a frame such that the first and second crushing shells define together a crushing chamber through which the material to be crushed is passed. A driving device positioned at a lower region of the main shaft is configured to rotate an eccentric assembly positioned about the shaft to cause the crushing head to perform a gyratory pendulum movement and crush the material introduced in the crushing chamber. Example gyratory crushers are described in WO 2008/140375, WO 2010/123431, US 2009/0008489, GB 1570015, U.S. Pat. No. 6,536,693, JP 2004-136252, U.S. Pat. No. 1,791,584 and WO 2012/005651.
Primary crushers are heavy-duty machines designed to process large material sizes of the order of one meter. Secondary and tertiary crushers are however intended to process relatively smaller feed materials typically of a size less than 35 centimeters. Cone crushers represent a sub-category of gyratory crushers and may be utilised as downstream crushers due to their high reduction ratios and low wear rates.
Typically, a spacer (or filler) ring is used to accommodate different geometries of different concaves and in particular to adapt the same topshell for mounting medium or fine sized concaves used in secondary and tertiary crushers in contrast to the much larger diameter coarse concaves that fit directly against the topshell and have a maximum diameter to receive large objects for crushing. WO 2004/110626 discloses a gyratory crusher topshell having a plurality of different spacer ring embodiments for mounting a variety of different concaves at the crushing region.
Typically, both the inner and outer crushing shells wear and distort due to the significant pressures and impact loading forces they transmit. In particular, it is common to use backing compounds to structurally reinforce the outer shell and assist with contact between the radially outward facing surface of the outer shell and the radially inward facing surface of the topshell. It is also typical to employ a backing compound at a region around the spacer ring for additional structural reinforcement and to ensure the various components mated together correctly. Example backing compounds include Korrobond 65™ and 90™ are available from ITW (‘Korroflex’) Ltd, Birkshaw UK; and KrushMore™ from Monach Industrial Products (I) Pvt., Ltd, India.
However, the majority of widely used backing compounds are disadvantageous for health and environmental reasons and require long curing times that extend the downtime of the crusher. Accordingly, there is a general preference to avoid their use. There is therefore a need for a gyratory crusher frame part that reduces or eliminates the requirement for use of backing compounds at the concave and filler ring regions.